Playing violent computer games such as Call of Duty does not make people more prone to violence, according to a new study that debunks years of accepted wisdom and warnings.
Scientists using brain scans and psychological questionnaires discovered that levels of aggression and the capacity for empathy in people who never play violent games were the same as in those who play games for hours each day.
The research undermines decades of claims, partly prompted by academic studies, that anti-social behaviour is linked to "shooter" games.
In 2015, one politician even blamed a spate of gun violence in Salford on "a diet of war games and Grand Theft Auto".
Grand Theft Auto 5, where players are part of a virtual gang and can be challenged to commit ever more audacious and violent crimes, currently tops a list of bestselling games.
The new survey waited at least three hours before conducting tests to determine the long-term psychological effects on a group who had played for at least two hours a day (though in many cases nearer four hours) for the previous four years.However, academics at the Hannover Medical School say previous studies may have been skewed because they often assessed participants' psychological state immediately after, or even during, a stint of violent gaming.
These participants, and others from a control group who did not game regularly, answered psychological questionnaires. Then, while their brains were being scanned in an MRI machine, they were shown images designed to provoke an emotional response.
As the images appeared, the participants were asked to imagine how they would feel if they were involved in the depicted situation.
The questionnaire revealed no differences in levels of aggression between the two groups, while the MRI data revealed similar neural responses.
Dr Gregor Szycik, who led the study, acknowledged that it was partly prompted by a rise in patients seeking clinical help for game addiction, but added: "We hope to encourage other research groups to focus their attention on the possible long-term effects of video games."